/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.objcoding.calcite.csv.translate;

import org.apache.calcite.adapter.java.JavaTypeFactory;
import org.apache.calcite.rel.type.RelDataType;
import org.apache.calcite.rel.type.RelDataTypeFactory;
import org.apache.calcite.rel.type.RelProtoDataType;
import org.apache.calcite.schema.impl.AbstractTable;
import org.apache.calcite.util.Source;

import java.util.ArrayList;
import java.util.List;

/**
 * Base class for table that reads CSV files.
 */
public abstract class CsvTable extends AbstractTable {
    protected final Source source;
    protected final RelProtoDataType protoRowType;
    private RelDataType rowType;
    private List<CsvFieldType> fieldTypes;

    /**
     * Creates a CsvTable.
     */
    CsvTable(Source source, RelProtoDataType protoRowType) {
        this.source = source;
        this.protoRowType = protoRowType;
    }

    public RelDataType getRowType(RelDataTypeFactory typeFactory) {
        if (protoRowType != null) {
            return protoRowType.apply(typeFactory);
        }
        if (rowType == null) {
            rowType = CsvEnumerator.deduceRowType((JavaTypeFactory) typeFactory, source,
                null, isStream());
        }
        return rowType;
    }

    /**
     * Returns the field types of this CSV table.
     */
    public List<CsvFieldType> getFieldTypes(RelDataTypeFactory typeFactory) {
        if (fieldTypes == null) {
            fieldTypes = new ArrayList<>();
            CsvEnumerator.deduceRowType((JavaTypeFactory) typeFactory, source,
                fieldTypes, isStream());
        }
        return fieldTypes;
    }

    /**
     * Returns whether the table represents a stream.
     */
    protected boolean isStream() {
        return false;
    }

    /**
     * Various degrees of table "intelligence".
     */
    public enum Flavor {
        SCANNABLE, FILTERABLE, TRANSLATABLE
    }
}
